Field of the Invention
This invention relates to a material handling device, more commonly known as a stock feeder or jig, for repetitively feeding or advancing uniform segments of stock material into a production machine which performs work on the segments of the stock material. Specifically, the invention relates to an improvement to such a device which renders it more readily adaptable to handle stock material of different widths.
Automatic stock feeders have been used with production machinery to attain relatively high production rates of articles manufactured from stock material which is wound on a spool or a roll. To handle the material on the spool or roll, as the case may be, some conventional feeders employ at least one set of clamps to grip and pull periodically during feeding and another set of clamps to hold the stock material in place while the machine works on a segment of the material to form an article of manufacture. For narrow stock material, a single gripper will suffice for handling each of the pulling and holding operations, but for wide stock material, say twelve inches or more, a pair of grippers is used at each end of the feeder. Some older types of feeders employ a pair of opposed rollers, instead of grippers (i.e., roll feeder), to perform these functions, but due to occasional slippage between the stock material and the rollers, these types of feeders have not proved as efficient and reliable as grip feeders.
Production operations performed by the machine may involve forming, cutting, milling, stamping, machining, etc., and the stock material from which the article is manufactured may comprise wire, metal tubing, sheet metal, bar steel, etc. or even non-metallic stock material, such as a plastic or fiber material. The feeder itself may be constructed to handle one particular size of stock material, or it may be adjustable, over some dimension thereof, to handle, for example, material of different widths. Obviously, if a production machine is to have versatility, the feeder should also be versatile in handling material of different widths and thicknesses.
If, during a production run for manufacturing an article, it becomes necessary to change the width of the feed path through which the material passes, normal practice is for a machine operator to shut down the machine, reposition a feed clamp and hold clamp located on one side of the feed path, and/or adjusts the beginning and end positions of the feed stroke on clamp carriages on both sides of the feeder, if required. These operations require a certain amount of time and skill on the part of the machine operator, and if it not performed properly and quickly, valuable production time can be lost. Therefore, it is advantageous to construct such feeders in a manner which enables them to be quickly adjusted with minimal skill.
U.S. Pat. No. 3,613,980 describes at least one type of stock feeder device which uses a pair of feed clamps for gripping a sheet of stock material and advancing a segment thereof and a pair of hold clamps for holding the segment at a fixed position while a machine works on the stock material. In this device, the hold and feed clamps also provide guiding edges against which the stock material abuts. So, each time it becomes necessary to use stock material of a different width, the entire clamp assembly on at least one side of the feed path must be repositioned. To accomplish repositioning, the feeder employs a clamp carriage that simultaneously displaces both the feed clamp and the hold clamp on one side of the feed path. The carriage, in turn, includes a guide rail and a manually driven actuator for moving the clamps to their new position. If a longitudinal change in stroke path is required, it is necessary to adjust the position of the clamps on each side of the feeder. The expense and complexity of such an arrangement can readily be appreciated.
U.S. Pat. No. 4,059,212 assigned to the assignee hereof describes a stock feeding apparatus, but it possesses only a single feed clamp actuator and a hold clamp actuator. This feeder is suitable for repetitively handling segments of relatively narrow stock material and is not adjustable, per se, to handle material of different widths.
In view of the foregoing, it is an objective of this invention to provide a material handling device of greater versatility for handing both narrow and wide stock material.
Another objective of this invention is to provide a material handling device possessing width-adjusting stock roller guides in front and rear portions thereof, which device is more readily adjustable to handle material of different widths.
Another objective of this invention is to provide a material handling devioe for automatically and repetitively feeding segments of stock material, which device can conveniently and quickly be adjusted with minimum time and skill thereby to reduce down time during stock changeover periods.
Another objective of the invention is to provide a material handling device wherein the respective pairs of feed clamps and hold clamps are mounted on respective front and rear blocks of the feeder in a fashion so that only the clamp heads, rather than the clamp carriage, need be repositioned for substantial changes in feed-path width; and only one block, rather than two clamp heads, need be adjusted for a change in stock length.
A further objective of the invention is to provide a material handling device for automatically feeding segments of stock material, which device is economical, reliable, and simple in construction.